Portable fluid fuel burning air heater



May 8, 1956 A. F. HUBBARD PORTABLE FLUID FUEL BURNING AIR HEATER Filed Oct. 15, 1951 5 Sheets-Sheet 2 INVENTOR.

ARTHUR E HUBBARD ATTORNEY y 8, 1956 A. F. HUBBARD 2,744,516

PORTABLE FLUID FUEL BURNING AIR HEATER Filed Oct. 15, 1951 5 Sheets-Sheet 3 29 o g] 76 9 76 -52 6 a V n J O AT 4 INVENTOR.

ARTHUR E HUBBQRD m Wm flTTORNEY May 8, 1956 A. F. HUBBARD PORTABLE FLUID FUEL BURNING AIR HEATER Filed Oct. 15, 1951 5 Sheets-Sheet 4 INVENTOR.

ARTHUR E HUBBQRD HT TORNE Y y 8, 1956 A. F. HUBBARD 2,744,516

PORTABLE FLUID FUEL BURNING AIR HEATER Filed 001;. 15, 1951 5 Sheets-Sheet 5 INVENTOR.

ARTHUR F HUBBARD Isa WWW A TTORNEY United States Patent PORTABLE FLUID FUEL BURNING HEATER Arthur F. Hubbard, Moline, Ill., assignor to American Air Filter Company, Inc., Louisville, Ky., a corporation of Delaware I Application October 13, 1951, Serial No. 251,215

14 Claims. (Cl. 126-110) The present invention relates to portable space heaters employing gasoline or similar fuel, and relates in particular to a heater unit having an easily demountable drive assembly.

Heaters of this type find an important application in military uses in arctic climates for heating temporary tank 2 which is mounted upon metal skids or runners r3,

and handles 4 are provided inrecesses on each sidefor:

The motor unit 6 within the box grasping the heater. is accessible through a top opening adapted to be closed by a hinged cover 7, and the air inlet and outlet are adapt- .1 ed to be covered by hinged covers 8 and 9 respectively,

the former cover being of the canopy type to excluderain or snow. The fuel tank 2 can be filled through a suitable connection 11 at the top, and the combustion exhaust flue ,12 can be covered by a hinged lid 13 when not in operation, to exclude rain or snow. I

buildings, aeroplane motors for easy starting, or in heating the working quarters during construction work. Because such heaters are employed in emergency services they must at all times be ready for service, and they must be capable of being repaired within a few minutes. The

difliculties in maintaining the heater serviceable are increased because in the exceedingly cold, sub-zero temperatures encountered in such regions, the operators wear heavy gloves and protective clothing and therefore cannot easily manipulate tools or small parts of a machine to make repairs.

It is my observation that the most common difficulties arising in this type of heater occur in the motor which drives the fuel pump and other mechanisms, and according to my invention a unit comprisingthe motor is easily demountable, so that it may be replaced by a like unit in operative condition. The construction also contemplates the interchangeability of a gasoline for an electric motor,

or vice versa for driving the fuel pump and other mecha- Figure 3 is a fragmentary section taken on line 3-3 of Figure 4 with the motor support. in elevation and the fuel pump removed the burner being shown diagramatically;

Figure 4 is an end elevation of Figure 2 as ,viewed from they left with the motor and other parts in dot-and-dash lines;

Figure 5 is a'fragmentary end elevation as viewed from.

the right end of Figure 2; I v

Figure 6 is an end elevation of the fan and housing as viewed along the line 66 of Figure 2;

Figure 7 is a plan view of the motor support and the housing with parts broken away;

Figure 8 is" a side elevation of an electric motor-driven replacement unit;

Figure-'9is a schematic view showing the heater employed'for warming the engines of an aeroplane;

Figure 10 is a perspective view of a modification with the'motor removed;

Figures ll and 12 are elevation views of details; and Figure 13 is a cross sectional view through the com- T bustion chamber cover with the burner in operative posi- 7 tion. 1

Referring to the' drawing-Figure 1, the portable heater comprises a. rectangular housing 1 surmounting a "fuel to form sockets 53 and 54.

The outer cylindrical jacket 15 of the heater (Figures 2 to 5) is braced by a stand 16 suitably connected to the jacket and the base plate.17 (Figures 2, and '7) ontopof. the fuel tank. A cylindrical heat exchanger 18 is ost, tioned withinthe jacket-15 and is held in spaced relation.

to the jacket by U-shaped pads or lugs 19 so as to provide an air passageway 21 betweenthe jacket and 'the'outer wall of the exchanger. I

having perforations 28 therein. This capvcarries a fuel burner 29, and the central portion of the exchanger pro- 7 vides a combustion chamber 31. It will be observedby reference to Figures 3 and 5 that the flattened spiral tubestaper down from their greatest cross-sectional area at the innermost portion toward the outermost portion, while the spaces between the tubes are substantially uniform.

The purpose of this taper will be explained later.

The rear edge of the jacket 15 is normal to the jacket axis for more than half of the circumference a-s indicat ed at 32 (Figure 2), and terminates in a lower cowl-like extension 33. A reenforcing ring 34 is secured within the jacket with its rear face 35 substantially flush with the edge 32 and carries a tapering deflector or baffle .36 secured thereto by radial straightening vanes 37. The vanes are secured to ring 34 and the deflector 36 by bent-over tabs or in any other suitable manner, and a, plenum chamber 38 thus is provided between the baflle 36'and the heatex changer 18.

A foot (Figure 4) made up of angle plates v39 atthe ends and a flanged U-strap41 is mounted upon the-cowl 33, and the foot carries a bracket comprisinga base bar 42; end plates 43, 44, and intermediate posts 45 and 46 1 extending therefrom. A magneto 47 is mounted uponend plate 43 by screws or the like and its shaft 48 extends through an opening in the plate 43 and-terminates in a flat coupling portion 49 between the plate and post 45.

Similarly, a fuel pump 50 is bolted upon end plate-44 with its shaft 51 extending therethro ugh and terminating in a flat coupling portion 52 between theplate and post their upper ends 46. Posts 45 and 46 are bifurcated at The motor unit 6 comprises a gasoline, engine housing 55 having a gear "chamber 56 fastened to the eng'lne'housing at one end, with the crankshaft (not shown) projecting into the gear housing. The engine may be of a type commercially available, equipped with a built-in magneto. A transverse shaft 57 extending from'bosses 58 on the gear chamber hasslotted ends 59 (Figure 8), the shaft being driven from the crankshaft through suitable gearing in the chamber. A fan housing comprises a rim por-,

tion 60 (Figure 6) and three radial arms 61, 62 and 63,

' .integral with a central plate 64 and therirn; is fastened to the gear housing 56 by bolting the central plate 64 thereto by cap screws 64' as shown in Figure6. A-fan drive shaft 65, which'may be the motor shaft or a separate shaft, extends from the front of the gearbox and hasthe fan or blower disc 66 removably secured thereto, as-by'a Patented May '8, 1956 The heat exchanger has an imperforate outer cylindrical wall 22 and end walls zsan'd, 24 (Figures 5 and 3), and flattened lune or crescent-F shaped tubes 25 spirally arranged therein provide longitudinal passageways 26 for air through the exchanger. End wall 23 has a central opening covered by a'c ap 27.

set screw in the hub. The blower comprises an impcrforate cup-shaped disc or rotor having blades 67 at its periphery, which blades clear the outer rim 60 of the housing and are in alignment with the straightening vanes 37in the jacket 15. The engine, gear housing, fan housing and fan thus constitute a unit, with the fan housing detachably secured thereto by cap screws 64', and the fan removable from the shaft. The motor exhaust pipe 68 (Figure 4) mates by a suitable slip connection with a pipe 69 leading to the combustion flue 12 so that the motor exhaust and burner exhaust are mingled therein.

In assembled position the sockets 53 and 54 receive the bosses 58 on the gear chamber and thus constitute cooperating indexing means, anclthey also support the motor assembly with the fan housing 60 opposite. ring 34, and the, flattened ends 49 and 52 of the magneto and fuel pump shafts received in the bifurcated ends 59 of the transverse shaft 57. Arms 61, 62 terminate in bosses 71, 71' having slots 72, 72' therein. Eye bolts 73 and 7 (Figures 2' and 7) are suitably pivoted to the jacket by hinges 74'and 74, the outer ends of the eye bolts be ing screw-threaded and carrying large hand nuts 75, 75' thereon. When the motor assembly is in operative position the eye bolts are swung rearwardly to the position shown in Figures 1 and 2 with the bolts in the slots 72, 72" of bosses 71 and 71', and by turning the hand nuts until they engage the bosses the fan housing 60 is clamped with its forward edge 76 in substantially sealing engagement with the rear face of the ring 34. The magneto, fan and fuel pumpare all driven from the motor.

From the foregoing description it will be seen that the fan or blower and the internal combustion engine constitute a unit which may be easily removed for replacementor repair. To remove the unit the hand nuts 75, 75 are turned back and the eye bolts 73, 73 are swung back to the position shown in Figure 7, whereupon the unit may be lifted from the sockets 53, 54, this lifting movement automatically disconnecting the tongues 49, 52 from the slots 59 in drive shaft 57 to disconnect the motor assembly from the magneto and pump. The slip joint of the motor exhaust pipe 68 with'pipe 69 also allows easy detachment thereof. By making the hand nuts 75, 75' of large size they can be manipulated by an operator wearing heavy gloves. The unit thus can be removed to a Warm place to make the necessary repairs or adjustments to the motor.

The blower supplies air for burning the fuel issuing from the burner 29 and also provides a fiow of air through the air tubes 25 of the heat exchanger. The flow producedby fan blades 67 passes through the straightening vanes 37 which eliminate eddy currents, and, as shown by the arrows in Figure 3, the air divides, some passing through the holes 28 to the burner, and some passing through space 21 and lengthwise through the tubes 25 and exiting at the end shown in Figure 5. Collapsible canvas ducts 76, 76 are connected in any suitable manner to the discharge end of the housing 15' and con duct the heated-air to any desired location. The products of combustion pass spirally through the spaces between tubes 25 to the wall 18, thereby heating the air flowing through the tubes, and the gases exit by fiue 12. Because wall 22 is exposed on the inside to the hot products of combustion, the air flowing through space 21 is heated and at the same time prevents the outer wall 15 from becoming hot. The temperature of the discharged air is controlled by a thermostat at the outlet (not shown).

As the combustion gases near the central combustion chamber are hotter than the gases near the periphery, there would be a tendency for the issuing current of air to be unequally heated, and before the overheated air becomes mixed with the lower-temperature air it is liable to scorch the collapsible canvas ducts 76, 76 that carry away the heated air. The capacity of the apparatus therefore must be limited to maintain the highest air temperature below the scorching point. This local overheating is avoided by having the air tubes 25 present a greater crosssectional area for flow of air near the center than near the periphery. Although the combustion gases at the center are at a higher temperature than near the periphery, this arrangement proportions the volume flow of air at the center and periphery (and at intermediate points) so that the temperature of the issuing air at the center and periphery is more nearly equal. Because of the elimination of local overheating of air, the apparatus can be operated at a greater capacity without danger of scorching the canvas ducts. It will also be noted that the fan maintains a higher pressure in the air flowing through the tubes and space 21 than in combustion chamber 31, so that leakage of products of combustion into the air stream is not possible.

The fuel burner 29 is of the bypass type and has a fuel line 78 leading from the pump outlet to the burner. A return fuel line 79 leads from the burner to a burner bypass regulating valve 81 connected by return line 82 to the fuel tank 2. This bypass valve is regulated by the thermostat located in the warm air outlet of the heater through a connection 83 so as to prevent overheating of the air. The thermostat controls valve 81 to vary the bypass or return flow from the burner, and thus modulates the burner flame. The greater the resistance to flow through the bypass, the more fuel will spray from the burner 29, and vice versa. The valve 81 is set by a suitable manual control 84 extending therefrom. The gasoline for the engine and burner is drawn by a tube 35 (Figure 7) connected to the fuel tank 2 through the strainer 86 and thence by line 86' to the fuel pump inlet. A line 87 from. the pump bypass line 83 leads to the carburetor of the engine. This line is provided with a quick detachable valved coupling 89, so that it may be easily disconnected from or connected to the carburetor inlet, merely by drawing back an outer sleeve on the coupling, when it is desired to remove the engine unit. Such couplings are commercially available and'therefore neednot be described in greater detail.

A manually controlled valve 89' is provided in pump bypass line 88 for initially regulating the fuel flow to the burner, and a primer pump 90 connects by a line 90 to the line 87' to supply fuel to the carburetor when starting. Check valves are provided in the various fuel lines to direct the proper flow of fuel as indicated by the arrows.

A spark plug 91 for igniting the gasoline issuing from the burner is connected by an electrical cable 92 to the magneto 47, this cable passing through a hole in the outer jacket 15 so as not to interfere with the fan.

In operation the fuel pump and magneto are driven by the motor, and the magneto furnishes electricity to the spark plug 91, while the fuel pump supplies gasoline to the burner 29 and the carburetor of the motor. The fan blows air past the vanes 37 into the plenum chamber 94 and some of the air passes through holes 28 in cap 27 to support combustion of gasoline in the chamber. products of combustion pass in a generally radial direction through the spaces between the tubes 25 to the exhaust pipe 95.

In the modification shown in Figures 10 to 12, the foot or bracket 98 is formed as a casting provided with integral posts 101, 102, and end plates 103 and 104. The magneto for operating the burner igniter is attached to plate 103 with its shaft extending through an opening therein, and a crank-105 is attached to the end of the shaft. The crank comprises an arm 106 having a projection 107 thereon. The pump shaft, which extends through a hole in plate 104, also carries a crank 108 comprising an arm 109 with a projection 110 thereon. Crank projections 107 and 110'each have a facing 111 of material having a low coefficient of friction. The motor and housing 56 are positioned with the bosses 58 in the sockets 53, and 54 and theshaft 57 has cranks 1'12, 113 at'its ends that engage. cranks 105, 108' respectively. It should be The.

noted that the crank plate or arm 109 is in the form of part of a circle of more than 180. This construction provides a dynamic counterbalance for the radial thrust on the pump bearing, as the curved portion provides a thrust opposing part of the drive thrust on the crank 110. Cranks 112 and 113 are similar, so only crank 112 will be described in detail. This comprises a plate or arm with a hub 114 thereon, and a projection 115 at the end of the arm, the arm being formed to provide a static and dynamic counterbalance. Projection 115 of crank 112 mates with projection 107 of crank 105, so that when shaft 57 turns it drives the magneto. Similarly, the projection 115 of crank 113 engages the projection 110 of crank 108 to drive the pump. It will be understood that the anti-friction pads or facings 111 may be on either one of the sets of cooperating cranks.

The cranks do not interfere with removal or attachment of the motor unit, and thus eliminate largely the manipulation of the shafts required to secure drive registration.

I claim as my invention:

1. A heating apparatus comprising: a housing supported with its axis generally horizontal and providing an abutting surface around one end; a heat exchanger in the housing providing passageways for flow of air to be heated; a fluid fuel burner in the housing associated with said heat exchanger for supplying heat thereto, said burner having an electrically actuated igniter ;a fuel pump connected to supply fuel to the burner; an electrical generator adjacent said abutting surface of said housing, connected to supply electricity to the igniter; said fuel pump and generator respectively having shafts transverse of the housing adjacent said abutting surface; a motor support adjacent said one end of the housing providing indexing means; a combined motor and fan unit having a power take off drive shaft transversely of said housing; coupling means on said fuel pump and generator shafts; complementary coupling means on said drive shaft; indexing means on said unit cooperating with the indexing means of the motor support to position said coupling means on said drive shaft for coupling with the coupling means on the generator and fuel pump; said unit having a fan housing adapted to abut said surface in coupled position of said drive shaft and pump and generator shaft; and clamping means for clamping together said fan housing and first housing.

2. A heating apparatus as specified in claim 1 wherein said motor support indexing means comprises a pair of forked posts providing upwardly open sockets between said pump and generator shafts; and said motor and fan unit indexing means comprises locating means on said unit adapted to be received in said sockets.

3. A heating apparatus as specified in claim 2 wherein said locating means comprise trunnions extending from said unit adapted to be received in said sockets.

4. A heating apparatus comprising: a housing having a heat exchanger forming a plenum chamber therewith at one end; said heat exchanger providing a combustion chamber with openings for flow of air from said plenum chamber into said combustion chamber; said heat exchanger having passageways therethrough connected with said plenum chamber and in heat exchange relation to said combustion chamber, for flow of air to be heated; a fluid fuel burner in said combustion chamber; an electrical fuel ignition means operatively associated with said burner; a motor support at said end of said housing adjacent said plenum chamber; a fuel pump connected to the burner and having a shaft extending transversely of said one end of said housing and terminating adjacent said burner; an electrical generator connected to said ignition means and having a shaft extending transversely of said one end of said housing and terminating adjacent said burner in axial spaced relation to said pump shaft; cou pling means at the ends of said shafts; a motor assembly including a motor, and having an open ended blower housing with a blower therein driven by the motor; said assembly having generator and pump drive shafts extending transversely between said pump and generator shafts and in alignment therewith; coupling means on said drive shafts adapted to cooperate with the coupling means on the fuel pump and generator shafts; said assembly having means cooperating'with the motor support for locating said drive shafts for registration with the pump and generator shafts and positioning of said blower housing in registration with said plenum chamber, whereby said blower forces air into said plenum chamber; and means for detachably clamping the blower housing to the first mentioned housingto secure the-motor assembly in position.

5. A heating apparatus as specified in claim 4 wherein:

said motor assembly includes a gasoline operated motor intake and an exhaust manifold; and

having a carburetor having a quickly detachable valved conduit connected between the carburetor intake of said motorassembly and said connection between the fuel pump and burner; a motor exhaust conduit; and a detachable connection between said motor exhaust manifold and said exhaust conduit.

6. A heating apparatus as specified in claim 4 wherein the burner is of the adjustable bypass type, and the fuel pump is connected to recirculate the fuel returned by the burner bypass.

7. A heating apparatus comprising: a housing having a heat exchanger providing a combustion chamber with openings for flow of air into said chamber, said exchanger having passageways therethrough in heat exchange relation to said chamber for flow of air to be heated; a fluid fuel burner in the combustion chamber; electrical fuel ignition means adjacent said burner; a motor supoprt at one end of said housing providing indexing means; a fuel pump having a fuel line connected to supply fuel to the burner and having a drive shaft; an electrical generator connected to the ignition means hav ing a drive shaft opposite said fuel pump shaft; a gasoline motor assembly having a blower housing open at the end to provide an annular flange, and a transversely arranged drive shaft, said motor assembly having a carburetor intake, an exhaust manifold, and indexing means coopcrating with the indexing means on said support for locating said transverse shaft the fuel pump and generator shafts and positioning said flange in abutting relation to the end of said housing; a quickly detachable valved conduit connected between the fuel line and the carburetor intake; coupling means on said fuel pump and generator shafts; complementary coupling means on said motor assembly drive shaft; means for detachably clamping the flange to the housing and cooperating with the indexing means to fasten the motor assembly in position with said motor shaft coupled to said generator and fuel pump shafts; 'a motor exhaust conduit; and a detachable connection between the motor exhaust manifold and said latter conduit.

8. Aheating apparatus adapted for selective operation by an electro-motor or internal combustion motor power assembly comprising: a cylindrical housing open at one end and supported with its axis generally horizontal; a fluid fuel burner in the housing; an electrical ignition means for said burner; a heat exchanger in the housing surrounding said burner and having openings communicating with the open end of said housing for the horizontal flow of air therethrough; a fuel pump connected to supply fuel to said burner supported adjacent the open end of the housing and having a drive shaft extending horizontally transversely ofthe housing; an electrical generator connected to the ignition means having a drive shaft extending horizontally transversely of the housing adjacent the open end thereof and in alignment with said pump drive shaft; a support for a motor assembly; coupling means on said shafts adapted to cooperate with comsubstantially in alignment with plementary coupling means on said motor assembly to couple saidshafts for, operation. by said motor assembly; andclamping means carried by the housing adjacent the open end.

9. The combination with the heating apparatus of claim of: a motor assembly having a motor therein, and axial and transverse shafts driven by the motor; coupling means associated with the, ends of said transverse shafts; a blower on the axial shaft; and an open end blower housing surrounding the blower carried by the motor assembly; projecting means on the motor housing assembly, adapted to be received by said support to position the transverse shaft in alignment with the pump shaft and generator shaft, and the blower housing in registration and engagement with the open end of the cylindrical housing; whereby said blower housing is adapted to be clamped to the cylindrical housing to secure the motor assembly in position.

10. A heating apparatus comprising: a housing providing an abutting surface around one end; a fluid fuel burner in the housing having an igniter; a fuel pump connected to supplyfuel to the burner and an electrical generator connected to supply electricity to the igniter, said pump and generator having shafts transverse of said housing adjacent said abutting surface; a motor support at the end of the housing; a motorunit having a transverse drive shaft; means on the unit received by the motor support to position the transverse drive shaft for coupling with the generator and fuel pump shafts, said latter means and motor support being engageable and disengageable by said relative transverse movement of said unit relative to the axes of the pump and generator shafts; cooperating coupling means adjacent the ends of said transverse shaft and pump and generator shafts engageable and disengageable by said relative transverse movement; and means for clamping said unit against the abutting surface about said housing.

11. A heating apparatus comprising: a base; a housing mounted upon said base; a heat exchanger in said housing providing passageways for flow of air to be heated; a fluid fuel burner in the housing associated with said heat exchanger for heating said passageways; electrical ignition means for the burner; an electrical generator mounted on said base adjacent one end of said housing and connected to said ignition means, said generator having a drive shaft extending transversely of said housing adjacent one end of said housing, and said shaft having coupling means adjacent said end; a motor support on said base providing indexing means adjacent said end of the housing; a motor unit having a drive shaft transverse of the end of said first housing with coupling means at atleast one end of said drive shaft, and having indexing means cooperating with the indexing means of the motor support to position said unit with the drive shaft and the coupling means thereon in aligned engagement with the generator shaft coupling means; said motor unit being positioned or removed by movement transverse to the axis of the generator shaft, and said coupling means malt ing engagement and disengagement by said transverse movement.

12. A heating apparatus comprising: a base; a housing mounted upon said base; a heat exchanger in said housing providing passageways for flow of air to be heated; a fluid fuel burner in the housing associated with said heat exchanger for heating said passageways; a fuel pump mounted on said base adjacent one end of said housing and connected to supply fuel to the burner, said pump having a drive shaft extending transversely of said hous' ing adjacent one end, and said shaft having coupling means adjacent said end; a motor support on said base providing indexing means adjacent said end of the housing; a motor unit having a drive shaft transverse of the end of said first housing with coupling means at at least one end of said drive shaft; and having indexing means cooperating with the indexing means of the motor support to position said unit with the drive shaft and the coupling means thereon in aligned engagement with the fuel pump shaft coupling means; said motor unit being positioned or removed by movement transverse to the axis of the pump shaft, and said coupling means making engagement and disengagement by said transverse movement.

13. A heating apparatus comprising an outer housing having a top opening at one end; a heat exchanger member in the housing having a vertical seating surface adjacent said opening, said heat exchanger comprising means defining a passageway therethrough for fiow of air to be heated; means operatively associated with said heat exchanger for supplying heat to the air as it passes through said passageway; 21 motor support adjacent said seating surface providing indexing means; a combined motor and fan housing unit member adapted to be inserted through said opening having indexing means cooperating with the indexing means on said support with the fan housing having an axial discharge opening and being connected to the heat exchanger in engagement with said seating surface with said discharge opening in registration with the heat exchanger to direct air axially to said heat exchanger; and clamping means swivelled on one member adjacent said top opening and adapted to engage the other member for securing the motor and fan housing unit member on said motor support with the fan housing in engagement with said seating surface, said clamping means being accessible through said top opening and being located to swivel away from said top opening to enable said motor and fan housing unit member to be inserted or removed through said opening.

14. A heating apparatus as specified in claim 13 wherein said clamping means comprises screw threaded bolts swivelled on said heat exchanger member and having screw threaded nuts thereon, said motor and fan housing unit member having slots to receive said swivelled bolts.

References Cited in the file of this patent UNITED STATES PATENTS 1,521,093 Hall Dec. 30, 1924 2,374,203 Holthouse Apr. 24, 1945 2,386,746 Hess Oct. 9, 1945 2,415,064 McCollum Jan. 28, 1947 2,479,906 Cole Aug. 23, 1949 2,579,507 McCracker Dec. 25, 1951 

